1. Field of the Invention
The present invention relates in general to a printing apparatus, and more particularly to a printer which is adapted to store font data received from an external device such as a host computer and is capable of printing characters in a given typestyle according to the stored font data, in response to a printing command also received from the external device.
2. Discussion of the Prior Art
There is known a printing apparatus in which characters are printed in a desired typestyle according to a corresponding batch of font data received from an external device. More specifically, two or more batches of font data which define a family of characters in respective different typestyles received from the external device are stored in the printing apparatus, so that a desired text consisting of characters represented by character code data also received from the external device can be printed in a desired typestyle selected from among various typestyles, which include typestyles suitable for formal documents, letters of invitation to a wedding ceremony or announcement of death and Christmas cards. A considerable number of typestyles (for alphabetic characters, in particular) are available, and floppy disks storing font data for many typestyles are commercially available. Batches of font data for the desired typestyles are supplied from the external device to the printing apparatus, so that the printing may be effected in a desired one of the typestyles.
There are different formats in which such font data define characters in a given typestyle. For example, the font data take the form of dot data consisting of bits ("1" or "0") indicative of the presence or absence of dots which cooperate to define a character, or outline data representative of an outline of a character. In the case of the outline data, the character outline may be defined by Bezier curves, circular arcs, spline curves, etc. On the other hand, a certain printer is operable with font data prepared in some formats, while another printer is operable with font data prepared in the other formats. Namely, a printer is not capable of using font data prepared in a given format. In view of this drawback, there is proposed a printer which has a function of converting a batch of font data in a certain format into the corresponding font data in a format with which the printer is compatible. For instance, a batch of font data in the form of dot data is converted into the font data in the form of outline dat defining character outlines by Bezier curves, and the obtained outline data are stored in a random-access memory and used for printing.
In a printer having such font data converting function, the font data obtained by conversion and stored in the random-access memory are lost or erased when the printer is turned off with electric power removed. Consequently, the user has to feed the appropriate font data from the external device to the printer, for preparing the font data in the format with which the printer is compatible. Usually, the conversion of font data for an alphabetic font (a family of alphabetic characters) requires about five minutes, and the required time of conversion increases with the degree of precision of the conversion and the number of the characters of the relevant font.
Accordingly, the conventional printer indicated above suffers from a waste of time for frequent conversion of font data, and accordingly lowered printing efficiency. Where the user wishes to print a document in a comparatively short time, the user has to use font data for a typestyle which is not desired by the user and not suitable for a document to be prepared, since the font data available for the desired typestyle are formulated in a format with which the printer is not compatible. Thus, the font data converting function cannot be effectively utilized in the conventional printer.